All applications are compiled to native ( XCode and Objective-C or Java ) applications. This build process can create 300MB+ files that are only needed during compile time. If disk space is something that is in short supply you can remove a few of the files to make life easier.
In your Titanium project under the build/iphone/Resources folder you can remove the libTiCore.a and libTitanium.a files. This will save you over 200MB of space without causing issues with your Titanium project. It is important to note that these files will be re-generated the next time you compile your application.
I exclude this directory from git and delete the contents when storing on the network or sending my project to another developer.